Wifi modem for the TS2068

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pastbytes
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Joined: Tue Dec 27, 2011 9:11 am
Location: Argentina
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Wifi modem for the TS2068

Post by pastbytes »

A few months ago I decided to connect a few Z80 machines to the internet, starting with the MSX computers, with a wifi modem connected to the printer port, continuing with the Pecos (a computer designed and manufactured in Argentina in the 80s), also through the printer port, and now finishing with the Timex Sinclair 2068, in this case with a wifi modem connected to the joystick port.

The goal of this project is to provide minimum connectivity to the network to be able to access BBS in ASCII format. To achieve this we use ESP8266 modules with the zimodem firmware (v3.5.4), and we need the machine to have 2 output pins and one input pin available on some port. The printer ports on the MSX and Pecos meet the requirements because they have 1 input pin and 9 output pins, the joystick port on the TS2068 is bidirectional, but unfortunately it is not programmable by pin but has to be all input or all output at the same time. This made the circuit the most complex of the 3.

To test the modem I wrote a minimalist terminal, Microterm, which we usually use for these experiments. Microterm only supports ASCII characters on a 32x24 character screen. To return to BASIC you have to press STOP (Symbol shift + A), and to run the terminal again, RUN 40.

On my website you have the instructions (in Spanish) to configure the modem, along with the schematic to assemble it and the link to download the terminal in .tap format.
https://www.pastbytes.com/wifimodem/#timex
wifimodem6.png
https://youtu.be/ArVEcRkw7eg
https://youtu.be/_T5Gv6lvEus
https://youtu.be/v2qkbH1V-CY
Last edited by pastbytes on Mon Oct 07, 2024 9:10 pm, edited 1 time in total.
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XavSnap
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Re: Wifi modem for the TS2068

Post by XavSnap »

Hi pastbytes,

Thanks for sharing!

Is it better to place diodes (1N4148) on the IN/OUT pinouts to avoid the signal back feed ?
(ever seen some problems on other computers)
Is it possible to drive the EPS using a 74HC00 to avoid inverters transistors/resistors?
Xavier ...on the Facebook groupe : "Zx81 France"(fr)
pastbytes
Posts: 30
Joined: Tue Dec 27, 2011 9:11 am
Location: Argentina
Contact:

Re: Wifi modem for the TS2068

Post by pastbytes »

Maybe it can be made to work with logic gates, I tried with 7414/40106 and i couldn't get it to work, and when I added a 1N4148 to the only input of the joystick port, the terminal stopped receiving data. These ports have their peculiarities because they are not designed to be used as outputs.
It would be interesting if someone else could try it so we can get a better or more compact circuit.
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XavSnap
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Re: Wifi modem for the TS2068

Post by XavSnap »

Hi pastbytes ,

We should try this :
opto.jpg
Xavier ...on the Facebook groupe : "Zx81 France"(fr)
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XavSnap
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Re: Wifi modem for the TS2068

Post by XavSnap »

Hi pastbytes,

The Kicad r.8 project is ready.
The Wifi card isn't include in the project, but i will publish it in an another tread. Here
modem_2068_1.jpg
modem_2068_2.jpg
Wiring diagram circuit:
modem_2068_Diagram.pdf
(98.1 KiB) Downloaded 130 times
Zipped Gerber:
MODEM_TURBO56K_Gerber.zip
(135.4 KiB) Downloaded 93 times
Kicad r.8 PCB:
modem_2068_TURBO56K_Kicad.zip
(521.65 KiB) Downloaded 107 times

Have fun.
Xavier ...on the Facebook groupe : "Zx81 France"(fr)
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